feat: add jailer_time binary for jailer perf tests

This binary just outputs the start and end time of
the jailer startup.

Signed-off-by: Egor Lazarchuk <yegorlz@amazon.co.uk>

Author: ShadowCurse

tests/conftest.py

@@ -274,6 +274,17 @@ def msr_reader_bin(test_fc_session_root_path):
     yield msr_reader_bin_path
 
 
+@pytest.fixture(scope="session")
+def jailer_time_bin(test_fc_session_root_path):
+    """Build a binary that fakes fc"""
+    jailer_time_bin_path = os.path.join(test_fc_session_root_path, "jailer_time")
+    build_tools.gcc_compile(
+        "host_tools/jailer_time.c",
+        jailer_time_bin_path,
+    )
+    yield jailer_time_bin_path
+
+
 @pytest.fixture
 def bin_seccomp_paths():
     """Build jailers and jailed binaries to test seccomp.

tests/host_tools/jailer_time.c

@@ -0,0 +1,19 @@
+// Copyright 2025 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+// This is used by `performance/test_jailer.py`
+
+#include <stdio.h>
+#include <time.h>
+
+int main(int argc, char** argv) {
+  // print current time in us
+  struct timespec now = {0};
+  clock_gettime(CLOCK_MONOTONIC, &now);
+  unsigned long long current_ns = (unsigned long long)now.tv_sec * 1000000000 + (unsigned long long)now.tv_nsec;
+  unsigned long long current_us = current_ns / 1000;
+  printf("%llu\n", current_us);
+
+  // print the --start-time-us value
+  printf("%s", argv[4]);
+}